"""coding=utf-8
Copyright 2018 The Google AI Language Team Authors.
Copyright (c) 2018, NVIDIA CORPORATION.  All rights reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License."""
import tensorflow as tf
import numpy as np


def float32_variable_storage_getter(getter,
                                    name,
                                    shape=None,
                                    dtype=None,
                                    initializer=None,
                                    regularizer=None,
                                    trainable=True,
                                    *args,
                                    **kwargs):
    """Custom variable getter that forces trainable variables to be stored in
       float32 precision and then casts them to the training precision.
    """
    storage_dtype = tf.float32 if trainable else dtype
    variable = getter(name,
                      shape,
                      dtype=storage_dtype,
                      initializer=initializer,
                      regularizer=regularizer,
                      trainable=trainable,
                      *args,
                      **kwargs)
    if trainable and dtype != tf.float32:
        variable = tf.cast(variable, dtype)
    return variable
